1. Technical Field
Various embodiments relate to a display control device and a display control method for controlling a display unit that includes a display panel such as an LCD (Liquid Crystal Display) panel for displaying images in electronic apparatuses such as an in-car display system and a mobile phone. Moreover, the various embodiments relate to a semiconductor integrated circuit device, a display device, and the like that include such a display control device.
2. Related Art
For example, an STN (Super-Twisted Nematic) display panel is used as an LCD panel. STN is a mode of a liquid crystal that uses Nematic liquid crystal in which the twist angle of the liquid crystal molecule is made large to about 180 to 270°. However, it is generally understood as a display method in a passive matrix type display panel that uses such liquid crystal.
In contrast, usage of an active matrix type display panel that uses TFTs (Thin Film Transistors) is increasing recently. However, when a switch to a TFT display panel having an arbitrary size is carried out in an electronic apparatus that uses an STN display panel, a large-scale change including a modification of software is required due to the change in the interface with the display panel. In view of this, it is desired that a switch to a TFT display panel can be realized without modification of the software.
As a related art, JP-A-9-34411 (paragraphs [0005] and [0007], claim 4) discloses an LCD controller that is capable of, by processing display data, displaying an image on an entire screen continuously without redrawing, when the resolution of the display is different from the number of pixels in the image data. The LCD controller is a display controller for displaying image data, which is stored in a display memory, on a liquid crystal display, includes a resolution ratio setting unit for setting a ratio between the number of pixels in the image data in the display memory and the resolution of the display, and a shift register for transferring the image data in the display memory to the display as serial data, and adjusts a shift clock of the shift register based on the output of the resolution ratio setting unit such that the serial data is suited to the resolution of the display, when the image data is transferred to the display.
According to JP-A-9-34411, since redrawing of a display memory to perform enlargement/reduction of an image is not required when the display data is transferred to a display, the image can be displayed according to the size of the screen without a modification of the software. However, in order to precisely deal with a plurality of types of display panels having different sizes, it is not sufficient just to adjust the ratio between the number of pixels in the image data and the resolution of the display, or to adjust the shift clock of the shift register, and various signals for controlling the display unit including the display panel need to be changed according to the size of the display panel.
Also, in JP-A-9-128182 (paragraphs [0001] and [0007], claim 1), a display device is disclosed that is connected to a display adapter circuit of a computer system, in a display system in which control data (data including a video signal and a timing parameter to generate a synchronization signal) is transferred between the computer system and the display device. The display device is a display device that includes a unit to generate a visual output in response to a plurality of data signals generated by the display adapter circuit, and includes a memory that stores control data in the form of a plurality of control codes for identifying the display device, and a device logic unit that responds to a command signal from the display adapter circuit for reading the control code from the memory and transmitting the control code to the display adapter circuit.
According to JP-A-9-128182, there is an advantage in that the programming of the display system does not need to be updated every time another display device is connected to an output port. Instead, the display device needs to transmit control data to the display adapter circuit in the form of a plurality of control codes for identifying the display device.